How did siege warfare neutralize the knight's usual advantage

Which of the following is an example of the pull factor known as economic migration? a. better educational opportunities pulling people towards a new country b. mexican laborers entering the us to work in agricultural jobs c. joining family members that are already in a new country d. crop failures driving people away from their country i am unsure on this question, i was thinking b? but i could be wrong.

Prior to which amendment were slaves counted as three-fifths of a personality

The antiwar protests of the late-1960s contributed to which of these? the election of lyndon johnson passage of the voting rights act passage of the 26th amendment the geneva accords